The present invention relates to a solid golf ball. More particularly, it relates to a solid golf ball having good shot feel when hitting and controllability as well as good flight performance and good cut resistance.
Recently, ionomer resins have been widely used for cover material of golf balls (e.g. Japanese Patent Publication No. 49-27093 etc.). Particularly, an ionomer resin is exclusively used as a cover resin for two-piece golf balls having a solid core. This is because the ionomer resin is superior in durability, cut resistance, rebound performance, etc. and it is easily processed.
However, since the ionomer resin has high hardness and rigidity, the resulting golf ball is poor in shot feel and controllability (ease of giving spin to the base) in comparison with balata rubber (transpolyisoprene) which has been used as a cover material for a multi-layer structured golf ball containing a thread rubber layer.
In order to improve shot feel and controllability of the ionomer-covered golf balls, softening the ionomer resin has been intensively studied.
For example, Japanese Patent Laid-Open Publication Nos. 1-308577 and 5-3931 suggest to blend or mix a hard ionomer resin with a soft ionomer resin prepared by neutralizing a terpolymer of an xcex1-olefin, an unsaturated carboxylic acid (e.g. acrylic acid, methacrylic acid, etc.) and an acrylate with sodium or a zinc ion, thereby improving shot feel and controllability.
However, blending with a soft ionomer resin as suggested by the above mentioned publications has not provided a shot feel which is close to the feel of a balata covered golf ball. Instead, the rebound performance and flight performance are adversely lowered by utilizing the soft ionomer resin and, therefore, sufficient technical effects have not been obtained.
Japanese Patent Laid-Open Publication No. 5-220240 suggests improving shot feel and controllability by blending the ionomer resin with a polymer containing glycidyl groups. According to this method, shot feel and controllability are slightly but insufficiently improved and thus ionomer-covered gold balls having desired characteristics, particularly, rebound performance, flight performance, etc., are still desired.
Under these circumstances, the present inventors have intensively studied the cover of the golf ball in an attempt to achieve the excellent shot feel and controllability, which is close to that of the balata-covered golf balls, and having the excellent flight performance and cut resistance of balls having covers made of an ionomer resin.
A main object of the present invention is to provide a golf ball having good shot feel and controllability as well as satisfactory flight performance and cut resistance.
The foregoing and other objectives of the present invention will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of the illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.